To change your desktop background in Windows 7, first of all you need to display your desktop: click the Show desktop button to the far right of the taskbar.
Then, right click in an area of the desktop where there are no icons and select Personalise. At the bottom, click on Desktop Background.
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This takes you to a panel where you can choose the picture that gets displayed as your background.
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Here, you can use the Picture Location dropdown list to choose the category of picture. They get displayed in the preview panel below. If you want to select a completely different picture to display, click on the browse button and navigate to an image on your hard drive.
When you find the folder where your picture is, select it and click OK. All the pictures that exist in that folder will be displayed in the preview panel. Here you can select the picture you want by clicking on it. You can select more than one picture by holding down the Ctrl key when you click additional pictures.
How do several pictures get displayed as your desktop background? At the bottom of the window are options where you can tell Windows to keep changing the desktop background image periodically.
When you’ve finished making your changes, click Save changes.